Monks of the Way of Shadow follow a tradition that values stealth and subterfuge. These monks might be called ninjas or shadowdancers, and they serve as spies and assassins. Sometimes the members of a ninja monastery are family members, forming a clan sworn to secrecy about their arts and missions. Other monasteries are more like thieves' guilds, hiring out their services to nobles, rich merchants, or anyone else who can pay their fees. Regardless of their methods, the heads of these monasteries expect the unquestioning obedience of their students.

Shadow Arts

Starting when you choose this tradition at 3rd level, you gain an amount of chi points equal to your monk level, which come back on a long rest. You can use your chi to duplicate the effects of certain spells. As an action, you can spend 2 chi points to cast darkness, darkvision, pass without trace, or silence, without providing material components. You can choose to ignore any harmful effects from your chi spells and you don't have to maintain concentration on them, instead they last for their full duration.

Additionally, you gain the minor illusion cantrip if you don't already know it.

Shadow Step

At 6th level, you gain the ability to step from one shadow into another. When you are in dim light or darkness, as a bonus action you can teleport up to 60 feet to an unoccupied space you can see that is also in dim light or darkness. You then have advantage on the first melee attack you make before the end of the turn.

Alternatively, you can choose to teleport 30-feet without needing dim light or darkness. If you teleport in this way, you can choose to leave behind a cloud of shadows, and you appear in a similar cloud of shadows at your destination. The shadows are darkness in the space you left and the space you appear in, and they dissipate at the end of your next turn. You then have advantage on the first melee attack you make before the end of the turn.

Advanced Shadow Arts

Starting at 6th level, you learn more about the shadow arts you live by. You can spend chi equal to the spell's level to cast blur, fear, hypnotic pattern, mirror image, or shadow blade, without providing material components. You can choose to ignore any harmful effects from your chi spells and you don't have to maintain concentration on them, instead they last for their full duration. And when you cast shadow blade with your chi, it's duration becomes 10 minutes.

Some of your shadow arts require your target to make a saving throw to resist the feature's effects. The saving throw DC is calculated as follows:

Shadow Arts save DC = 8 + your proficiency bonus + your Wisdom modifier

Cloak of Shadows

By 11th level, you have learned to become one with the shadows. When you are in an area of dim light or darkness, you can use your action to become invisible. You remain invisible until you make an attack, cast a spell, or are in an area of bright light for 10 minutes.

Additionally, when you use a shadow art that has a casting time of one action, you can use flurry of blows as a bonus action without spending ki.

Chi Restoration

At 11th level, you can enter a special meditation to restore your abilities. Once per day when you finish a short rest, you regain an amount of chi equal to your monk level.

Oppurtunist

At 17th level, you can exploit a creature's momentary distraction when when you attack from the shadows. Whenever you make an attack roll against a creature that's in dim light or darkness, the attack is considered a critical hit.